1. Air Flow Optimization for Remediation using SPARG Diane Fink Liz Hilkert

2. Significance and Objective  Optimal airflow rates are important in remediation –Ensure maximum contaminant volatilization –Prevent channeling  Determine ideal capillary pressures for a one meter soil column –varying water table heights

3. SPARG Information  Unix based program for one or two dimensional column simulations  Uses finite element-Galerkin's formulation  The airflow simulation model that is the basis for AirFix –Includes contaminant transport

4. SPARG Calibration  Only dependable data from 2D model  Capillary Head of 10.15 m  Calibration successful

5. Sensitivity Analysis Sensitive Variables Capillary PressureSaturation Atmospheric PressureAll Soil Lambda PorosityAve Saturation Sensitivity 0.3400.109Min-Def1.003 0.3900.125Def-Max0.998 0.4400.141 Atmospheric Pressure Capillary Pressure at Y =0.4 Sensitivity 8.000-0.524Min-Def29.032 10.0000.276Def-Max6.509 12.0001.076

6. SPARG Inputs  Constant Inputs: –Psubd: 0.2 m –Soil Lambda: 3.4 –Porosity: 0.39 –Grid: 1,10 –Grid Division: 0.1 m –Atmospheric Pressure: 10 m 20 elements 22 nodes

7. Varied SPARG Inputs  Water Table Height: –Half of Sand Height: 0.33 m –Full Sand Height: 0.67 m  Airflow Entry Rate (nodes 1 and 2): –Varied by increasing air entry pressure –Minimum for half full: 10.53 m –Minimum for full: 10.87 m

8. Effect of Air Entry Pressure at Full Water Table Height (0.67 m) Saturation Capillary Pressure

9. Effect of Air Entry Pressure at Half Water Table Height (0.33 m) Capillary Pressure Saturation

10. Graphical Trends  Capillary pressure: –linear relationship with column height –indirectly proportional to water table height –directly proportional to air entry pressure at lower water table heights  pressures converge as air reaches the top of the column, which is atmospheric  Saturation: –nonlinear relationship with column height –directly proportional to water table height –indirectly proportional to air entry pressure at lower water table heights  saturation levels converge as air reaches the top of the column, which is atmospheric

11. Conclusions  Full Water Table Height (0.67 m): –Air entry pressure range: 10.871 – 10.89 m  Half Water Table Height (0.33 m): –Air entry pressure range: 10.531 – 10.55 m

12. Thank You Questions?